Territory



No. 6|6,3H. Patented Dec. 20, I898. c. GRACEY.

GRUSHING MILL STAMP STEM.

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UNITED STATES PATENT OFFICE,

CHARLES GRAOEY, OF KINGMAN, ARIZONA TERRITORY.

CRUSHING-MILL STAMP-STEM.

SPECIFICATION forming part of Letters Patent No. 616,311, dated December 20, 1898. Application filed April 1, 1898- Serial No. 676,042. (No model.)

To all whom it may concern.-

Be it known that I, CHARLES GRAGEY,a citizen of the United States, residing at Kingman, county of Mohave, Territoryof Arizona, have invented an Improvement in Crushing- Mill Stamp-Stemsg and I hereby declare the following to be a full, clear, and exact de scription of the same.

My invention relates to improvements in the stamp-stems of crushing-mills.

It consists, essentially, in such a construction of the stamp as will prevent the breakage of the stem at its junction with the stamphead into which it is fixed, and in details of construction, which willbe more fully explained by reference to the accompanying drawing, in which the figure illustrates the stamp-stem, showing its connection with the stamp-head.

In stamp-mills, such as usually employed for crushing quartz and other rock, the stampshoe is fixed into a cylindrical head, andinto the upper end of this head is fitted a stem movable vertically in guides and made to rise and drop alternately by the action of cam and tappet. In this operation of constant lifting and dropping the fall of the stamp on the rock is more or less irregular, striking sometimes on one side and sometimes onthe other, and the result is a twisting or bending strain upon the stamp-stem at its junction with the head. This action taking place ceaselessly will in time crystallize and weaken the stem so that it breaks off at the j unction with the stamp-head. Thisis of such certain and regular occurrence that all stamp-stemsare tapered at each end, so that when one end has been broken off the stem may be taken out, reversed, and the other end inserted into the stamp-head, so that it can be used until it too has been broken. My invention is designed to prevent this breakage of the stamp-stems.

In the drawing, A is the stamp-head, of any usual pattern, having a tapered hole bored in the center of the upper end. Into this tapered hole the correspondingly-tapered end of the stamp-stem B is inserted, and it binds and fits closely enough to secure the two together.

0 is an opening made transversely through the stamp -head to receive a driftingtool, which, passing below the lower end of the stamp stem, serves to force the latter out when it is necessary to separate it from the stamp-head.

Ordinarily these stems are tapered, so as fit the whole length of the taper in the stamp head, and by reason of this snug fit the length of the taper, which is usually five or six inches, more or less, is sufficient to give a leverage which acts, as above described, to break the stem by reason of the stamp sometimes striking its full force on one extreme edge and sometimes on another.

In my invention I make the taper of the stamp stemto fit the upper partof the stamphead, as shown at a, for a distance not greater than the diameter of the stamp-stem, which may be two and one-half or three inches or sometimes more, The lower portion of the stem, which continues down to the drift-opening 0, is turned or otherwise made slightly smaller than the tapered opening in the stamp-head, as shown at b, so that by mak ing it a thirty-second or a sixteenth of an inch smaller the lower part of the taper 'is out of contact with the lower part of the tapered opening in the stamp head. This allows for a slight movement either one way or the other of this lower portion when any sudden wrench or side pressure is brought upon the upper part of the stamp-head by the reasons above described, and this yielding prevents the shock and strain upon the stem which would eventually break it at its junction with the stamp-head.

. By making the length of the taper which fits into the stamp-head less than the diameter of the stamp-stein there will be no leverage upon the latter sufticientto cause it to break, and I have found by experience that they will not break when constructed in this manner.

By making the lower end smaller and ex .tending it down to the drift-opening O the and a stein having a short tapered portion to closely fit the upper portion only of the central opening and having a portion below said tapered portion of less diameter than the latter to maintain this prolonged portion out of contact with the remaining portion of the walls of the tapered opening in the stamp head, the lower end of the said reduced portion extending into the drift-opening whereby -it may be engaged to detach the stem from 10 the head.

In witness whereof I have hereunto set my hand.

CHARLES GRACE'Y.

Witnesses S. H. NoURsE, JESSIE 0. 133011112. 

